1. Field of the Invention
The present invention generally relates to high conduction cooling (HCC) structures used for dissipating heat produced by integrated circuits or the like and, more particularly, to HCC structures of the interdigitated cooling fin variety.
2. Description of the Prior Art
Large-sized computer systems typically include many closely spaced integrated circuit devices which can be packaged separately or together. Collectively, these integrated circuit devices produce a large amount of heat which, if not dissipated properly, will adversely impact on the performance of the computer system. The problem of proper heat dissipation from closely packed integrated circuit devices is well known. For example, U.S. Pat. No. 4,263,965 to Mansuria et al., U.S. Pat. No. 4,381,032 to Cutchaw, U.S. Pat. No. 4,483,389 to Balderes et al., U.S. Pat. No. 4,535,841 to Kok, U.S. Pat. No. 4,685,211 to Hagihara et al., and U.S. Pat. No. 4,765,400 each show different arrangements for dissipating heat from closely spaced integrated circuit devices and each arrangement includes a separate cooling base element for contacting each of the integrated circuit devices and a bulk heat transfer element positioned in heat transfer relationship with all of the cooling base elements. Heat is transferred from the integrated circuit device to the cooling base element and then to the bulk heat transfer element. From the bulk heat transfer element, heat is either dissipated to the air or is carried away by a refrigerant fluid which contacts the bulk heat transfer element.
Recently, interdigitated cooling fin designs have been used in the large-sized computer environment for dissipating heat from closely packed integrated circuit devices. For example, U.S. Pat. No. 4,770,242 and U.S. Pat. No. 4,800,956 each show heat dissipation arrangements for integrated circuits comprised of cooling bases with upwardly projecting cooling fins which interact with the downwardly projecting cooling fins of a bulk heat transfer element. The cooling fins on each element are arranged as spaced parallel rows and resemble a comb in cross-section. The cooling base and bulk heat transfer element are put together such that the parallel rows of cooling fins on the cooling base are interdigitated with the parallel rows of cooling fins on the bulk heat transfer element. The cooling fins significantly increase the surface area which can be used for heat transfer. One problem with the interdigitated cooling fin design is that the heat transfer elements must be machined to fairly exacting tolerances in order to fit together properly; hence, the cost of production is higher. Another problem with the interdigitated design relates to the efficiency of heat transfer between the cooling base which contacts the integrated circuit device and the bulk heat transfer element. Heat transfer between thermally conductive elements is more efficient when the elements touch one another as compared to when they are separated by a space. However, in most prior art interdigitated HCC structures, the machining process used to produce the cooling fins results in a small gap being created between the cooling base and the bulk heat transfer element which reduces the efficiency of heat transfer between the cooling base and the bulk heat transfer element.